Here's what the ```parse_mapping_file*``` functions are currently doing:

- stripping of whitespace is only performed on table cells (including sample IDs), **not** on the column header. Quotes (```"```) are removed from both the header and table cells

- if quotes and leading/trailing whitespace are to be stripped (the default behavior in most QIIME scripts, including the R code), all quotes (```"```) are removed **first** and then the value is stripped

Can you please add this information to the description?